Chen X.,Hangzhou Tea Research Institute |
Wang Y.,Zhejiang University |
Wu Y.,Peking University |
Han B.,China Jiliang University |
And 3 more authors.
International Journal of Biological Macromolecules | Year: 2011
Hot-water extracts of low-grade green tea were precipitated with ethanol, deproteinized with trichloroacetic acid, neutralized with NaOH and fractionated by DEAE-cellulose DE-52 column chromatography to yield three (3) of unexplored polysaccharide-conjugate fractions termed gTPC1, gTPC2 and gTPC3. Monosaccharide and amino acid composition, contents of total neutral sugars, proteins and moistures, HPGPC distribution and Zeta potentials of gTPC1-3 were investigated. Exposure of human umbilical vein endothelial (HUVE) cells to high glucose (33. mM) for 12. h significantly decreased cell viability relative to normal glucose control (p< 0.001). As compared with cell injury group, gTPC1-3 at all of three dose levels (50, 150 and 300 μg/mL) were found to possess remarkably protective effects on HUVE cells against impairments induced by high glucose in a dose-dependent manner (p< 0.05, p< 0.001). To contribute toward our understanding of the cell-based protection mechanism of gTPC1-3, the latter were subjected to self-oxidation of 1,2,3-phentriol assay, and their scavenging effects were observed as 55.1%, 47.6% and 47.9% at the concentration of 300 μg/mL, respectively. On the basis of the fact that high glucose-induced endothelial dysfunction involves in the overproduction of reactive oxygen species (ROS) and contributes to the vascular complications in patients with diabetes, inhibitory effects of gTPC1-3 on high glucose-mediated HUVE cell loss are, at least in part, correlated with their potential scavenging potency of ROS. Taken together, gTPC1-3 could be developed as non-cytotoxic candidates of therapeutic agent for diabetic vascular complications. © 2011 Elsevier B.V.
Ren G.,Anhui Agricultural University |
Ren G.,Hangzhou Tea Research Institute |
Wang S.,Anhui Agricultural University |
Ning J.,Anhui Agricultural University |
And 5 more authors.
Food Research International | Year: 2013
Near-infrared spectroscopy (NIRS) combined with chemometric tools was utilized as a rapid analysis method to assess quality and to differentiate geographical origins of black tea. A partial least squares (PLS) algorithm was employed for the calibration of models predicting the levels of caffeine, water extract, total polyphenols, and free amino acids, while a factorization method was proposed to trace black tea from different geographical origins. In the calibration set, the root mean squared error of cross validation (%) and the correlation coefficient (R) for caffeine, water extracts, total polyphenols and free amino acids were 0.102%, 0.654%, 0.552%, and 0.248% and 0.983, 0.977, 0.975, and 0.943, respectively. In the prediction set, the root mean squared error of prediction and R for the corresponding constituents were 0.160%, 0.685%, 0.594%, and 0.273% and 0.955, 0.962, 0.954, and 0.927, respectively. The identification accuracy for black tea from different geographical origins reached 94.3%. This study demonstrated that NIR spectroscopy can be successfully applied to rapidly determine the main chemical compositions and geographical origins of black tea. © 2012 Elsevier Ltd.
PubMed | Hangzhou Tea Research Institute and U.S. Center for Disease Control and Prevention
Type: Journal Article | Journal: Journal of separation science | Year: 2016
A novel triethylenetetramine-functionalized magnetic graphene oxide composite was prepared and used as a magnetic solid-phase extraction adsorbent for the fast detection of ten trace-level phenolic environmental estrogens in environmental water. The synthesized material was carefully characterized by scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, and X-ray photoelectron spectroscopy to confirm the structure and components. The adsorption and desorption conditions of the adsorbent toward phenolic environmental estrogens were optimized in detailed to obtain the best extraction recovery and elution efficiency. Under the optimum conditions, the limits of detection of the method for ten phenolic environmental estrogens were in range of 0.15-1.5 ng/L, which was lower than the reported methods for phenolic environmental estrogens detection in literatures. This could be contributed to the unique structure and property of the as-prepared material. The developed method was successfully applied for the determination of environmental water samples with recoveries ranging from 88.5 to 105.6%.
PubMed | Hangzhou Tea Research Institute and Jiangnan University
Type: | Journal: Carbohydrate polymers | Year: 2015
The effect of four industrial tea derivatives (tea polyphenols [TPS], tea water-soluble extracts [TSE], tea polysaccharides [TSS], and green tea powder [GTP]), on the retrogradation of wheat starch was investigated using texture profile analysis (TPA), differential scanning calorimetry (DSC), rapid viscosity analysis (RVA), and the -amylase-iodine method. The addition of the four tea derivatives resulted in decreased hardness and increased cohesiveness of the starch gel as shown by the TPA test. The DSC data demonstrated an increase in the enthalpy change of starch gelatinization and a decrease in the enthalpy change of starch recrystallite dissociation. The RVA results indicated that the peak viscosity, representing the intermolecular forces of wheat starch, was reduced after addition of TPS, TSE, and TSS, respectively, but was increased by GTP. Furthermore, the half crystallization time in the Avrami equation almost doubled after the separate addition of the tea derivatives.
Sun J.,Zhejiang University of Technology |
Huang J.,Zhejiang University of Technology |
Zhang A.,Zhejiang University of Technology |
Liu W.,Zhejiang University |
Cheng W.,Hangzhou Tea Research Institute
Journal of Hazardous Materials | Year: 2013
Phthalate esters (PAEs), a group of emerging organic contaminants, have become a serious issue arousing much attention for their ubiquitous presence and hazardous impact on the environment. This study provides the first data on distribution of PAEs in the sediments in the Qiantang River, Zhejiang Province, China, and the inference with urbanization and river flow regime. PAEs were detected in all 23 sediment samples analyzed, and the total concentrations of their 16 congeners in sediments ranged from 0.59 to 6.74μg/g dry weight (dw), with the geometric mean value of 2.03μg/g dw. Of the 16 PAE congeners, di-n-butyl phthalate (DnBP), diisobutyl phthalate (DiBP), and di(2-ethylhexyl) phthalate (DEHP) were present in all sediment samples. The PAEs concentrations in urban regions were higher than those in rural regions because of higher discharge of PAEs from plastic materials in urbanized areas. Concentrations of PAEs were positively correlated with sediment organic matter (fOM) and negatively correlated with logistic value of annual average flow volume at sample sites. River flow regime modified by man-made dams significantly affected the distribution of PAEs. Analysis of congener composition of PAEs indicated that the DEHP was predominant congener in the Qiantang River. The normalized concentration of DEHP exceeded recommended environmental risk limit (ERL). © 2013 Elsevier B.V.
Wu Q.-J.,Fujian Agriculture and forestry University |
Dong Q.-H.,Fuzhou Huaming Tea Research Institute |
Sun W.-J.,Fujian Agriculture and forestry University |
Huang Y.,Fujian Agriculture and forestry University |
And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2014
This study aimed to construct objective and accurate analytical models of tea categories based on their polyphenols and caffeine. A total of 522 tea samples of 4 commonly consumed teas with different fermentation degrees (green tea, white tea, oolong tea, and black tea) were analyzed by high-performance liquid chromatography (HPLC) coupled with spectrophotometry, utilizing ISO 14502, as analytical tools. The content of polyphenols and caffeine varied significantly according to differently fermented teas, indicating that these active constituents may discriminate fermentation degrees effectively. By principal component analysis (PCA) and stepwise linear discriminant analysis (S-LDA), the vast majority of tea samples could be successfully differentiated according to their chemical markers. This study yielded three discriminant functions with the capacity to simultaneously discriminate the four tea categories with a 97.8% correct rate. In classification of oolong and other teas, there were one discriminant function and two equations with best discriminant capacity. Furthermore, the classification of different degrees of fermentation of oolong and external validation achieved the desired results. It is suggested that polyphenols and caffeine are the distinct variables to establish internationally recognized models of teas. Copyright © 2014 American Chemical Society.
Zhong Z.,Ningbo University |
Dong Z.,Ningbo University |
Yang L.,Ningbo University |
Chen X.,Hangzhou Tea Research Institute |
Gong Z.,Ningbo University
Experimental and Therapeutic Medicine | Year: 2012
Green tea catechins are known to function as anticancer agents via inhibition of carcinogenesis during the initiation, promotion and progression stages. Many potential mechanisms have been proposed, yet the precise mechanism of lung cancer prevention by green tea catechins remains unclear. microRNAs (miRs) are a class of 21-24 nucleotide small non-coding RNAs and play critical roles throughout cellular development and regulation. Emerging evidence demonstrates that tea catechins influence the expression of miRs in human cancer cells to inhibit tumorigenesis. Both let-7a-1 and let-7g were detected in the human lung cancer cells treated with tea catechins. The cell viability and cell cycle were analyzed after tea catechins treatment. In the present study, we found that tea catechins upregulated the tumor-suppressor miRs, let-7a-1 and let-7g, in lung cancer cell lines. The upregulation of let-7a/7g repressed the expression of their targets, C-MYC and the regulatory protein of LIN-28, at the mRNA and protein levels. Moreover, the cell growth assay indicated that tea catechins significantly inhibited cell proliferation, and the flow cytometric analysis revealed an increase in the number of cells in the G2/M phase and a decrease in the number of cells in the S phase after treatment with tea catechins. These observations suggest that green tea catechins mediate the inhibition of proliferation of lung cancer cells through the let-7 signaling pathway.
Tan R.,Shanghai University of Traditional Chinese Medicine |
Tan R.,Hangzhou Tea Research Institute |
Niu M.,Shanghai University of Traditional Chinese Medicine |
Zhao J.,Shanghai University of Traditional Chinese Medicine |
And 2 more authors.
Journal of Drug Targeting | Year: 2014
In order to improve the lymphatic targeting efficiency of anti-cancer agent vincristine sulfate (VCR), the poly (butylcyanoacrylate) nanoparticles (VCR-PBCA-NPs) were prepared by emulsion polymerization and modified superficially with Pluronic F127. These prepared nanoparticles with (F127-VCR-PBCA-NPs) and without surface modification (VCR-PBCA-NPs) were characterized and their lymphatic targeting efficiencies were evaluated in vitro and in vivo. The results showed that VCR was released more sustained from both kinds of VCR-loaded nanoparticles, compared with the VCR solution. The up-taking efficiency of VCR into raji cells was enhanced by F127-VCR-PBCA-NPs, compared with the VCR-PBCA-NPs or VCR solution. Lower clearance (CL) of VCR from the systemic circulation and higher lymphatic targeting efficiency of VCR were observed for F127-VCR-PBCA-NPs than the VCR-PBCA-NPs or VCR solution, and F127-VCR-PBCA-NPs showed greater antitumor efficacy than the VCR-PBCA-NPs or VCR solution in the human Burkitt's lymphoma (raji)-bearing nude mice. These findings suggest that superficially modified nanoscale carriers might be promising vehicles for chemotherapeutic agents in the treatments of metastatic tumors and malignant lymphoma. © 2014 Informa UK Ltd. All rights reserved: reproduction in whole or part not permitted.
Wang Y.,Zhejiang University |
Ying L.,Zhejiang University |
Sun D.,Zhejiang University |
Zhang S.,Hangzhou Tea Research Institute |
And 2 more authors.
International Journal of Molecular Sciences | Year: 2011
Supercritical carbon dioxide (SC-CO 2) extraction of bioactive compounds including flavonoids and phenolics from Ampelopsis grossedentata stems was carried out. Extraction parameters such as pressure, temperature, dynamic time and modifier, were optimized using an orthogonal array design of L 9 (3 4), and antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and ferrous ion chelating (FIC) assay. The best conditions obtained for SC-CO 2 extraction of flavonoids was 250 bar, 40 °C, 50 min, and with a modifier of methanol/ethanol (1:3, v/v), and that for phenolics extraction was 250 bar, 40 °C, 50 min, and with a modifier of methanol/ethanol (1:1, v/v). Meantime, flavonoids and phenolics were found to be mainly responsible for the DPPH scavenging activity of the extracts, but not for the chelating activity on ferrous ion according to Pearson correlation analysis. Furthermore, several unreported flavonoids such as apigenin, vitexin, luteolin, etc., have been detected in the extracts from A. grossedentata stems. © 2011 by the authors; licensee MDPI, Basel, Switzerland.
PubMed | Hangzhou Tea Research Institute and Hubei Normal University
Type: | Journal: Journal of the science of food and agriculture | Year: 2016
White tea has received increasing attention of late as a result of its sweet taste and health benefits. During the brewing of white tea, many factors may affect the nutritional and sensory quality of the resulting infusions. The present study aimed to investigate the effect of various infusion conditions on the taste components of Fuding white tea, including infusion time, ratio of tea and water, number of brewing steps, and temperature.Brewing conditions had a strong effect on the taste compound profile and sensory characteristics. The catechin, caffeine, theanine and free amino acid contents generally increased with increasing infusion time and temperature. Conditions comprising an infusion time of 7min, a brewing temperature of 100C, a tea and water ratio of 1:30 or 1:40, and a second brewing step, respectively, were shown to obtain the highest contents of most compounds. Regarding tea sensory evaluation, conditions comprising an infusion time of 3min, a brewing temperature of 100C, a tea and water ratio of 1:50, and a first brewing step, resulted in the highest sensory score for comprehensive behavior of color, aroma and taste.The results of the present study reveal differences in the contents of various taste compounds, including catechins, caffeine, theanine and free amino acids, with respect to different brewing conditions, and sensory scores also varied with brewing conditions. 2016 Society of Chemical Industry.